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MBB enabling services and improving user experience

Advanced EPC

Advanced EPCMBB enabling services and improving user experience

1 Introduction ........................................................................................................................1

2 EPC standards timeline ........................................................................................................2

3 Challenges and opportunities for the Advanced EPC ............................................................3

4 Advanced EPC Key Features ................................................................................................4

4.1 Signaling congestion control ............................................................................................4

4.2 User plane congestion control ..........................................................................................4

4.3 Carried grade WiFi integration .........................................................................................5

4.4 Voice service for LTE users ...............................................................................................6

4.5 Video enhancement .........................................................................................................7

4.6 Proximity based services ..................................................................................................8

4.7 Group communication system enabler .............................................................................9

4.8 Machine type communications ........................................................................................9

4.9 Architecture enhancement for application interworking ................................................11

4.10 XML based access to PCRF .............................................................................................12

4.11 SGi traffic steering .........................................................................................................12

5 Conclusions .......................................................................................................................14

6 Annex: Abbreviation ..........................................................................................................15

3GPP’ s 4G mobile system LTE/EPC has been developed by the mobile

industry in the last few years during 3GPP releases 8 and release 9 to meet

the continuously growing service requirements of MBB. The overall system

consists of the radio system LTE and the Evolved Packet Core (EPC). A

further evolution of the LTE radio system has been done in the time frame of

3GPP release 10 and is called LTE-Advanced. The corresponding overall

system has been selected as an ITU 4G technology option. It should be

noted that LTE denotes the radio system, but is also the official terminology

for marketing the overall mobile system of LTE and EPC.

During the following 3GPP releases on the network side the further evolution

of the EPC is targeting at enabling of more profitable services and improving

user experience, both bringing added value for the whole mobile market.

Service enabling has thus become an important topic after basic EPC

features have been specified during initial 3GPP releases. In this whitepaper

it focuses on the current phase of EPC, which is denoted as Advanced EPC.

It takes advantage of the excellent radio capability of LTE and LTE-

Advanced.

The current phase of the Advanced EPC is facing the following challenges:

·High penetration of smart phones with a variety of applications causing

traffic of virtually any pattern and volume.

·Fast traffic growth with growth of revenues not keeping pace.

·Increasing diversity of service types and their related Quality of Experi-

ence.

To address those challenges, the following areas of improvement have been

identified:

·Enhancements that mitigate or prevent system overload.

·Capacity boosting by WiFi integration and offloading.

·Enhancements for enabling key services and other new business opportu-

nities.

·Introduction of new service enablers.

In this whitepaper it provides an overview on how the EPC timeline devel-

oped, considers the specific challenges and opportunities for the Advanced

EPC and describes the different key features of the Advanced EPC that are

intended to address the challenges and opportunities.

1 Introduction

1

The initial activities on the LTE/EPC system started already in 2004. The

radio access system and the related core network have been designed to

provide a new mobile system targeting at higher spectral efficiency, higher

peak data rates, shorter round trip times and frequency flexibility. This radio

access system is called Evolved UTRAN (E-UTRAN), and the core network

is the Evolved Packet Core (EPC). Both together form the Evolved Packet

System (EPS).

EPC is designed by 3GPP not only as the core network for the LTE/E-

UTRAN radio access system but as well for its predecessors GERAN and

UTRAN. The EPC is thus an evolution of the packet core that was designed

for GERAN/UTRAN. Main differences to the earlier packet core are the new

access interface adjusting for the specifics of the E-UTRAN/LTE radio

access, a simplified bearer management scheme solely relying on network

controlled bearer services and a split into control and user plane network

entities. EPC also contains capabilities for using Non-3GPP access tech-

nologies (e.g. WiFi) as access systems.

EPS is a pure packet system and, besides SMS, it does not provide any

telecom services for end users like circuit switched telephony. A separate IP

Multimedia Subsystem using the bearer services of the EPS provides

multimedia telephony for the end user. To enable initial EPS deployments

without an IP Multimedia Subsystem (IMS), 3GPP defined the “Circuit

Switched Fallback” feature (CSFB), which transfers the device from LTE to

GERAN or UTRAN for performing circuit switched calls, but enjoying for IP

based services the high bandwidth and low latency of E-UTRAN/LTE. For

deployments with EPS and IP Multimedia Subsystem 3GPP defined the

“Single Radio Voice Call Continuity” features (SRVCC) to enable a step-

wise rollout of E-UTRAN/LTE coverage by continuing IP Multimedia Subsys-

tem provided services as Circuit Switched services via GERAN/UTRAN

when a user leaves E-UTRAN/LTE coverage.

2 EPC standards timeline

2

Figure 2a. EPC standards timeline

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Release 8 Release 9 Release 10 Release 11 Release 12 Release 13 and later on

LTE LTE-Advanced Further LTE evolution on LTE-B/C

EPC: basic Advanced EPC: Service Enabling for MBB Further EPC evolution

In the last few years the Telco industry experienced significant changes.

One significant trend is the move of Internet services from personal comput-

ers to mobile devices. This trend got accelerated especially with the explo-

sive penetration of smart phone.

Another trend is that in many developed markets the penetration rate of

mobile subscribers is reaching some saturation. This increases the interest

of looking for new revenue opportunities and extending mobile services to

other potential markets (Enterprise, government, machine communications,

etc).

The whole mobile industry eco-system started to change when smart phone

begun to dominate the terminal market. One significant change is that

traditional telecom services like voice and message get more and more

challenged by the so-called Over-The-Top (OTT) applications using the

mobile system as a transparent bit-pipe. However, there is more and more

interest in offering better services to the users by making the mobile system

application-aware and providing added value, like QoS, for OTT applica-

tions.

The following activities have been identified for Advanced EPC to proactively

cope with the above trends and challenges:

·Make the mobile system more robust and efficient, in order to manage the

increasing amount of connected devices, but also the increasing variance

of connection types, e.g. from M2M, and save OPEX and CAPEX.

·Enlarging the system capacity, in order to meet the requirements from

huge traffic volume, which is still in a process of growing fast.

·Support new services and further improve the Quality of Experience for

key services like voice and video.

·Offer network capabilities to applications for better supporting the diversity

of Internet services and facilitating an expansion of the mobile ecosystem

towards including applications.

After the basic EPC features, i.e. providing high performance IP bearer

services for MBB, had been completed within 3GPP release 8 and release 9,

work started on enabling voice, multimedia and machine type communica-

tions services, like emergency call, CSFB/SRVCC enhancements, M2M

related features. The currently ongoing phase of advancing the EPC targets

at improving or creating business opportunities for operators by enhancing

existing or developing new EPC services and features. The timeline of the

Advanced EPC is shown in the figure 2a.

3 Challenges and opportunities for the Advanced EPC

3

4.1 Signaling congestion control

The origin of the investigation on signaling overload in the core network was

a specific case of a Radio Network Controller (RNC) restart leading to a

flood of UE registering with the network in a short time period. The affected

HLR could not answer all the requests, which made the situation even worse

since UEs retried the registration. Similar issues were identified for other

scenarios and other network entities.

3GPP has thus started to look at these issues with the setup of a study item

on Core Network Overload (CNO).

One of the issues being studied was the load handling for Diameter applica-

tions. Comparable to SS7, a new logical function is introduced, the Diameter

Load Manager. It influences the route selection when a congested node is

detected.

Another investigated issue is about the optimization for the reporting of user

location information. The basic idea of avoiding too much location report

traffic in the network is to adjust the granularity of the location reporting

according to the needs, e.g. by defining a specific area for which a report is

wanted.

A third issue is on the overload control for GTP-C interfaces. Different

approaches are evaluated for reducing the traffic towards loaded nodes

caused by too many GTP-C requests.

4.2 User plane congestion control

mobile network resources. Especially in RAN, user plane congestion occurs

more frequently and becomes a serious problem to the operators. Mecha-

nisms are wanted, which reduce the occurrence of congestion and alleviate

congestion in a quick and smooth manner. 3GPP is studying this under User

Plane CONgestion management (UPCON).

Today application/user services with their different QoS needs can be

identified and treated by using separate bearers. However in many deployed

networks, services with different QoS requirements often share the same

bearer, i.e. the default bearer. In this case the RAN has no information on

differences among these services being conveyed in the shared bearer and

transfers all IP packets in a uniform way according to the allocated bearer

QoS. When congestion happens, RAN may need to decide on delaying or

4 Advanced EPC Key Features

4

discarding IP packets based on the bearer QoS. A shared bearer prevents

the RAN from taking efficient approaches for avoiding/alleviating congestion

specifically per application/user service. Marking the user data packets with

an identifier for their priority during congestion (the so called Flow Priority

Identifier,FPI ) is a solution that provides the RAN with extra information.

The PGW/GGSN marks the data packets with the Flow Priority Identifier

based on the subscription, application type and possibly other criteria.

According to this information the RAN can shape or discard the data traffic

specifically per priority of the application or user service.

Another way of RAN node congestion mitigation is notifying affected

applications, which may then try to adjust the service while maintaining the

Quality of Experience as good as possible. For example, a video application

could change its media codec or employ video compression. Other applica-

tions may trigger providing services based on load notifications, e.g. for

delivering push data depending to the network traffic status.

4.3 Carried grade WiFi integration

WiFi is more and more regarded as an important part of mobile operator

networks. It can be connected to the EPC via S2a, S2b and S2c interfaces.

But how to effectively utilize WLAN infrastructure using the so far standard-

ized means is still a problem.

In Advanced EPC, the S2a path with GTP will be enhanced to support UEs

accessing EPC via WiFi with minimum changes for the UE IP stack. Further,

concurrent multiple connections need to be supported for WiFi access and

seamless handover between 3GPP and WiFi (considered under 3GPP

release 12 work item SaMOG) to reduce efforts for implementing carrier

grade WiFi support in UEs.

A huge number of WLAN Access Points are deployed all over the world.

From all those available WLAN Access Points most cannot be accessed by

mobile subscribers. Often it is because many are just providing private

services. As a consequence, useless access attempts consume large

quantity of UE battery power and impact the user experience. An overall

network discovery and selection mechanism considering PLMN selection

and Hotspot 2.0 ANQP (Access Network Query Protocol) elements enables

the UE to efficiently connect to the network via the most proper WLAN AP. A

cellular assisted WLAN discovery and selection mechanism will improve the

user experience when moving between 3GPP and WLAN without user

perception. To decrease the time required for the mobility with WLAN, a new

security architecture is designed to make the UE achieving substantially

4.2 User plane congestion control

mobile network resources. Especially in RAN, user plane congestion occurs

more frequently and becomes a serious problem to the operators. Mecha-

nisms are wanted, which reduce the occurrence of congestion and alleviate

congestion in a quick and smooth manner. 3GPP is studying this under User

Plane CONgestion management (UPCON).

Today application/user services with their different QoS needs can be

identified and treated by using separate bearers. However in many deployed

networks, services with different QoS requirements often share the same

bearer, i.e. the default bearer. In this case the RAN has no information on

differences among these services being conveyed in the shared bearer and

transfers all IP packets in a uniform way according to the allocated bearer

QoS. When congestion happens, RAN may need to decide on delaying or

5

discarding IP packets based on the bearer QoS. A shared bearer prevents

the RAN from taking efficient approaches for avoiding/alleviating congestion

specifically per application/user service. Marking the user data packets with

an identifier for their priority during congestion (the so called Flow Priority

Identifier,FPI ) is a solution that provides the RAN with extra information.

The PGW/GGSN marks the data packets with the Flow Priority Identifier

based on the subscription, application type and possibly other criteria.

According to this information the RAN can shape or discard the data traffic

specifically per priority of the application or user service.

Another way of RAN node congestion mitigation is notifying affected

applications, which may then try to adjust the service while maintaining the

Quality of Experience as good as possible. For example, a video application

could change its media codec or employ video compression. Other applica-

tions may trigger providing services based on load notifications, e.g. for

delivering push data depending to the network traffic status.

faster access to WLAN.

Network controlled IP flow mobility further enables the UE to route IP traffic

simultaneously over 3GPP radio access and WLAN, and easily moving IP

traffics between the radio access technologies smoothly based on operator’s

policy.

4.3 Carried grade WiFi integration

WiFi is more and more regarded as an important part of mobile operator

networks. It can be connected to the EPC via S2a, S2b and S2c interfaces.

But how to effectively utilize WLAN infrastructure using the so far standard-

ized means is still a problem.

In Advanced EPC, the S2a path with GTP will be enhanced to support UEs

accessing EPC via WiFi with minimum changes for the UE IP stack. Further,

concurrent multiple connections need to be supported for WiFi access and

seamless handover between 3GPP and WiFi (considered under 3GPP

release 12 work item SaMOG) to reduce efforts for implementing carrier

grade WiFi support in UEs.

A huge number of WLAN Access Points are deployed all over the world.

From all those available WLAN Access Points most cannot be accessed by

mobile subscribers. Often it is because many are just providing private

services. As a consequence, useless access attempts consume large

quantity of UE battery power and impact the user experience. An overall

network discovery and selection mechanism considering PLMN selection

and Hotspot 2.0 ANQP (Access Network Query Protocol) elements enables

the UE to efficiently connect to the network via the most proper WLAN AP. A

cellular assisted WLAN discovery and selection mechanism will improve the

user experience when moving between 3GPP and WLAN without user

perception. To decrease the time required for the mobility with WLAN, a new

security architecture is designed to make the UE achieving substantially

6

faster access to WLAN.

Network controlled IP flow mobility further enables the UE to route IP traffic

simultaneously over 3GPP radio access and WLAN, and easily moving IP

traffics between the radio access technologies smoothly based on operator’s

policy.

4.4 Voice service for LTE users

LTE/EPC is a mobile system for providing mainly IP bearer services. Voice

services are however still important services and their support is considered a

crucial factor for the success of LTE/EPC deployments. Voice services are

provided either by deploying a subsystem for VoIP/VoIMS or by falling back to

GERAN/UTRAN enabled Circuit Switched (CS) domain. CS Fallback (CSFB)

and IMS/SRVCC (Signal Radio Voice Call Continuity) are the two key features

for enabling voice services with the EPS.

CSFB is considered the first step as it relies on fallback to legacy systems. It

has been launched commercially with the early deployment of LTE/EPC and

will continue to be supported in Advanced EPC at least for supporting roamers.

To further improve the user experience Huawei developed “Ultra-Flash

CSFB” (refer to figure 4a) as enhancements of the standardized CSFB. It

optimizes the call-setup time for CS fallback, which is accomplished by the

Advanced EPC network due to initiating call setup in parallel with the UE fall

back to GERAN/UTRAN access network. With those optimizations, it provides

an equivalent or even less call-setup time compared to a native 2G/3G CS call.

IMS and SRVCC (including video SRVCC and its enhancements) are the

long term voice solutions for voice over LTE/EPC and are supposed to

support both voice (including HD voice) and video services in Advanced

EPC. With CSFB and IMS deployed, two voice service options are available

that may complement each other.

Figure 4a: Ultra-Flash CSFB

Sv

GERAN/UTRANLTE

Ultra - Flash CSFB

MSC MME

SGs

Sv

Figure 4b. Mobile usage forecast of 2015

7

4.5 Video enhancement

Video traffic has emerged as the dominant traffic in today's Internet (Per

Huawei mLab report - H2 2012, streaming application will account for 40% to

60% of mobile usage in 2015, figure 4b). How to deliver such massive traffic

with the required QoE becomes critical to operators.

Progressive download has been a popular mechanism for video service in

Internet. But it seems not working well in the cellular environment and proper

architecture enhancements are needed in order to support mobile streaming

services. In an industry-wide collaboration including multiple SDOs 3GPP

and partners developed the method DASH (Dynamic Adaptive Streaming

over HTTP). However, it is running on the application level and thus pro-

vides limited tooling for operator control. A network control enhancement to

DASH [see figure 4c] is being discussed in 3GPP Release 12 to support

more business scenarios like network aware adaptation, precise QoS

control, etc.

Figure 4c. DASH with network control

Advertisement

High bit rate

Medium bit rate

Low bit rate

HTTP Adaptive Proxy (HTTP Cache)

Client 1

Client 2

Client N

Server

47.83%

37.89%

1.73%

1.71%

8.44%

0.19% 1.87% 0.33%

SouthEast Asia

35.95%

43.97%

7.45%1.39%

9.06%

0.34% 0.92% 0.91%

China

34.74%

40.72%

4.67%

1.25% 13.31%

1.50%

2.85% 0.96%

West Europe

18.77%

58.20%

10.81%

North America

27.66%

55.62%

3.03%

2.08% 7.96%

2.22% 0.82% 0.60%

Latin America

0.91%

4.07%

1.87%

4.36%

1.01%

Web browsingStreamingFile transferIMSNSVOIPEmailGaming

8

4.6 Proximity based services

Direct Device-to-Device discovery and data exchange services exist already

for a long time. Bluetooth and WiFi Direct (802.11) provide examples of such

service offerings. The 3GPP system introduces such functionality, named

Proximity Services, within its release 12.

The main driver for this is the interest to use the EPS for providing profes-

sional mobile radio services for public safety usage, like for police or

ambulance. Some additionally considered usage scenarios are offering

3GPP proximity services for commercial or consumer applications, such as

the discovery of other users belonging to the same application and who are

in proximity or to enable direct LTE or WiFi communication between users or

devices that are in proximity to each other. Proximity communications are

also considered as an option for offloading traffic from the network and thus

improving cost and resource efficiency.

3GPP proximity services include the discovery service and the communica-

tion service. Each may be used separately as an enabler for other, specifi-

cally application services. Proximity discovery and communication service

will be available as functionality of the E-UTRAN/LTE access system. Public

safety users or applications may use those services based on pre-configured

permissions also when there is no coverage or connectivity with the mobile

system. Consumer usage is only permitted with authorization by the mobile

system on a per usage basis.

Specifically for enabling Public Safety application services the 3GPP

proximity services need to provide relay functionality for extending radio

coverage in various scenarios.

Another option is to take advantage of IP multicast technology which is

supposed to be a cost effective way of delivering common content traffic to a

group of users. The multicast technology can be applied to the cellular

system with certain customization. MBMS (and eMBMS) is a cellular

multicast technology for UMTS/LTE networks, which could be the base for

further work. 3GPP has started to work on on-demand MBMS for this

purpose. On-demand MBMS would allow operators to identify the common

video traffic (carried over DASH) or deliver different video traffic with

carrousel style, then shift the traffic from unicast mode to multicast mode.

This transportation mode switch should of course consider information like

user location, number of users accessing the same content, etc. to achieve

reasonable gains.

4.6 Proximity based services

Direct Device-to-Device discovery and data exchange services exist already

for a long time. Bluetooth and WiFi Direct (802.11) provide examples of such

service offerings. The 3GPP system introduces such functionality, named

Proximity Services, within its release 12.

The main driver for this is the interest to use the EPS for providing profes-

sional mobile radio services for public safety usage, like for police or

ambulance. Some additionally considered usage scenarios are offering

3GPP proximity services for commercial or consumer applications, such as

the discovery of other users belonging to the same application and who are

in proximity or to enable direct LTE or WiFi communication between users or

devices that are in proximity to each other. Proximity communications are

also considered as an option for offloading traffic from the network and thus

improving cost and resource efficiency.

3GPP proximity services include the discovery service and the communica-

tion service. Each may be used separately as an enabler for other, specifi-

cally application services. Proximity discovery and communication service

will be available as functionality of the E-UTRAN/LTE access system. Public

safety users or applications may use those services based on pre-configured

permissions also when there is no coverage or connectivity with the mobile

system. Consumer usage is only permitted with authorization by the mobile

system on a per usage basis.

Specifically for enabling Public Safety application services the 3GPP

proximity services need to provide relay functionality for extending radio

coverage in various scenarios.

9

4.7 Group communication system enabler

These enhancements are also driven by the interest of using the EPS for

providing Professional Mobile Radio (PMR) services. The adoption of the

3GPP system as a common global mobile broadband system is caused

specifcally by the interest in broadband features for group communications,

which are not offered by current PMR systems, like ETSI TETRA or US P25.

These current PMR systems provide group communications as narrow band

services. The interest in using advanced features and services that require

broadband support made 3GPP’ s EPS a good candidate for this. While

proximity services cover mainly the service support under conditions without

suitable radio coverage, the group communications system enablers

consider all other aspects needed for operating PMR services via an EPS. It

may be possible to use existing features, like EPS packet bearer services or

roaming, without specific modifications. Special considerations are on

efficient system resources usage. Especially for scenarios with many users

in the same area multicast data delivery may be needed and therefore the

usage of eMBMS or other enhancements need to be considered. Other

challenges that may require specific systems enablers are the strict timing

requirements from such mission critical services.

4.8 Machine type communications

Machine to Machine (M2M) communication is identified as one of the most

interesting chances for operators to generate new revenues specifically as

this business is in addition to providing services for the human being

population, whose growth already reached already saturation in some

markets. A specific characteristics and therefore challenge of M2M is the

often low ARPU per single device, which may be compensated by large

device populations under the same contract, given that commissioning,

operation and services can be managed in a cost efficient way. These are

the areas where specific system features intend to enable or improve such

business. Mobile M2M traffic worldwide is now doubling every year and the

proportion of 3G and 4G M2M devices will increase continuously.

M2M brings specific challenges to the network due to the potential massive

number of devices to be supported and the fact that those may act in a

coordinated manner. The basic capability for the mobile network is therefore

to efficiently maintain and manage the connectivity for a huge number of

M2M Devices. In addition, network robustness has to cope with situations

where a large number of M2M devices perform coordinated actions, e.g.

transfer data at the same point in time or change the network when nodes of

another network recover. Means for access control at different levels of the

mobile system have been already specified to cope with such or other

congestion situations to maintain normal service for other users. In addition,

for efficient handling of large number of connections a special feature for

device triggering was introduced by enhancing the existing SMS capability.

For the current phase of the Advanced EPC, the focus is more on improved

support for a large variety of M2M application scenarios. Specifically low

cost, low power consumption and efficient handling of small data transfers

have been identified as critical issues.

Further 3GPP features and services will be provided and offered to applica-

tions or service platforms as enablers for the new emerging M2M business.

Like the new future proof messaging service, which may be considered a

more powerful SMS service, it transfers efficiently data units of up to 1kB

size, independently from IP connectivity. Another example is the enhance-

ment of 3GPP’ s discontinuous reception mechanisms that allow for

frequent data transfers with less system processing and are also suited to

reduce the device’ s battery power consumption. Further, a new device

sleep state mechanism may enable devices with infrequent communications

needs, e.g. tracking devices that report location every hour or day, to run

years without replacing the battery. As soon as the work load situation

allows for it, 3GPP may also continue to define a new monitoring framework

to provide M2M and other service platforms with a comprehensive status

overview about device, service and subscription conditions. This and other

interworking with platform or service enablement layers is becoming more

and more important for creating applications and services with added value.

4.7 Group communication system enabler

These enhancements are also driven by the interest of using the EPS for

providing Professional Mobile Radio (PMR) services. The adoption of the

3GPP system as a common global mobile broadband system is caused

specifcally by the interest in broadband features for group communications,

which are not offered by current PMR systems, like ETSI TETRA or US P25.

These current PMR systems provide group communications as narrow band

services. The interest in using advanced features and services that require

broadband support made 3GPP’ s EPS a good candidate for this. While

proximity services cover mainly the service support under conditions without

suitable radio coverage, the group communications system enablers

consider all other aspects needed for operating PMR services via an EPS. It

may be possible to use existing features, like EPS packet bearer services or

roaming, without specific modifications. Special considerations are on

efficient system resources usage. Especially for scenarios with many users

in the same area multicast data delivery may be needed and therefore the

usage of eMBMS or other enhancements need to be considered. Other

challenges that may require specific systems enablers are the strict timing

requirements from such mission critical services.

10

4.8 Machine type communications

Machine to Machine (M2M) communication is identified as one of the most

interesting chances for operators to generate new revenues specifically as

this business is in addition to providing services for the human being

population, whose growth already reached already saturation in some

markets. A specific characteristics and therefore challenge of M2M is the

often low ARPU per single device, which may be compensated by large

device populations under the same contract, given that commissioning,

operation and services can be managed in a cost efficient way. These are

the areas where specific system features intend to enable or improve such

business. Mobile M2M traffic worldwide is now doubling every year and the

proportion of 3G and 4G M2M devices will increase continuously.

M2M brings specific challenges to the network due to the potential massive

number of devices to be supported and the fact that those may act in a

coordinated manner. The basic capability for the mobile network is therefore

to efficiently maintain and manage the connectivity for a huge number of

M2M Devices. In addition, network robustness has to cope with situations

where a large number of M2M devices perform coordinated actions, e.g.

transfer data at the same point in time or change the network when nodes of

another network recover. Means for access control at different levels of the

mobile system have been already specified to cope with such or other

congestion situations to maintain normal service for other users. In addition,

for efficient handling of large number of connections a special feature for

device triggering was introduced by enhancing the existing SMS capability.

For the current phase of the Advanced EPC, the focus is more on improved

support for a large variety of M2M application scenarios. Specifically low

cost, low power consumption and efficient handling of small data transfers

have been identified as critical issues.

Further 3GPP features and services will be provided and offered to applica-

tions or service platforms as enablers for the new emerging M2M business.

Like the new future proof messaging service, which may be considered a

more powerful SMS service, it transfers efficiently data units of up to 1kB

size, independently from IP connectivity. Another example is the enhance-

ment of 3GPP’ s discontinuous reception mechanisms that allow for

frequent data transfers with less system processing and are also suited to

reduce the device’ s battery power consumption. Further, a new device

sleep state mechanism may enable devices with infrequent communications

needs, e.g. tracking devices that report location every hour or day, to run

years without replacing the battery. As soon as the work load situation

allows for it, 3GPP may also continue to define a new monitoring framework

to provide M2M and other service platforms with a comprehensive status

overview about device, service and subscription conditions. This and other

interworking with platform or service enablement layers is becoming more

and more important for creating applications and services with added value.

4.8 Machine type communications

Machine to Machine (M2M) communication is identified as one of the most

interesting chances for operators to generate new revenues specifically as

this business is in addition to providing services for the human being

population, whose growth already reached already saturation in some

markets. A specific characteristics and therefore challenge of M2M is the

often low ARPU per single device, which may be compensated by large

device populations under the same contract, given that commissioning,

operation and services can be managed in a cost efficient way. These are

the areas where specific system features intend to enable or improve such

business. Mobile M2M traffic worldwide is now doubling every year and the

proportion of 3G and 4G M2M devices will increase continuously.

M2M brings specific challenges to the network due to the potential massive

number of devices to be supported and the fact that those may act in a

coordinated manner. The basic capability for the mobile network is therefore

to efficiently maintain and manage the connectivity for a huge number of

M2M Devices. In addition, network robustness has to cope with situations

11

4.9 Architecture enhancement for application interworking

There is increasing interest in the mobile network to become aware of OTT

applications. This awareness would facilitate the providing of network

services in a more resource efficient way and also with better user experi-

ence. For instance, the network could optimize the radio resource schedul-

ing for certain applications. For these requirements mechanisms already

exist like SAPP (Service Awareness & Privacy Policy), SIRIG (Service

Identification for improved Radio utilization In GERAN) or are under develop-

ment like for User plane congestion control (UPCON) described above.

Also letting applications being aware of the network status (e.g. congestion)

may help to further improve the user experience. For example, a video

server could proactively adapt the codec if it gets a congestion pre-

notification, thereby avoiding any annoying video interruption. Such aware-

ness for applications should be addressed in a general way. A proposed

framework is shown as below in figure 4d.

Figure 4d: Application Interworking Framework for Advanced EPC

A new function called AIF is introduced between the service layer and the

mobile network to abstract the network capabilities in a systematic way and

thus unifying and opening the network capabilities towards application

service providers.

UE eNodeB

MME SGW/PGW

HSS

PCRF

AIF: Application Interworking Functionality

Service Layer

AS

AIF

EPCRAN

where a large number of M2M devices perform coordinated actions, e.g.

transfer data at the same point in time or change the network when nodes of

another network recover. Means for access control at different levels of the

mobile system have been already specified to cope with such or other

congestion situations to maintain normal service for other users. In addition,

for efficient handling of large number of connections a special feature for

device triggering was introduced by enhancing the existing SMS capability.

For the current phase of the Advanced EPC, the focus is more on improved

support for a large variety of M2M application scenarios. Specifically low

cost, low power consumption and efficient handling of small data transfers

have been identified as critical issues.

Further 3GPP features and services will be provided and offered to applica-

tions or service platforms as enablers for the new emerging M2M business.

Like the new future proof messaging service, which may be considered a

more powerful SMS service, it transfers efficiently data units of up to 1kB

size, independently from IP connectivity. Another example is the enhance-

ment of 3GPP’ s discontinuous reception mechanisms that allow for

frequent data transfers with less system processing and are also suited to

reduce the device’ s battery power consumption. Further, a new device

sleep state mechanism may enable devices with infrequent communications

needs, e.g. tracking devices that report location every hour or day, to run

years without replacing the battery. As soon as the work load situation

allows for it, 3GPP may also continue to define a new monitoring framework

to provide M2M and other service platforms with a comprehensive status

overview about device, service and subscription conditions. This and other

interworking with platform or service enablement layers is becoming more

and more important for creating applications and services with added value.

12

4.10 XML based access to PCRF

Nowadays mobile operators enable dedicated support for their own or 3rd

party applications via the Rx interface, which is based on Diameter protocol.

However, 3rd party application providers typically use XML based protocols

more frequently. Changing those applications to support Diameter, if

possible, would create additional efforts and is therefore no cost efficient

option. In order to resolve this issue, an XML based access from the AF to

the PCRF should be specified as a new XML based Rx variant or provided

by a protocol converter (referring to figure 4e). Both options may be needed

to support different deployment scenarios.

4.11 SGi traffic steering

Currently a range of Value Added Service (VAS) enablers are deployed

between P-GW SGi interface and the edge router to the Internet Service

Provider. These VAS enablers may include traffic compression, video

optimization, web caching, HTTP header enrichment, Firewall, etc. These

enablers are important for providing services in a cost efficient and stable

way. Good VAS deployment will not only improve the user experience, but

may also create additional revenue from enhancing or processing data in

accordance with business relation.

There is however a need for an efficient routing of user data traffic to avoid

unnecessary traversing of individual VAS components, which are not

needed according to the policy applicable to the specific user data traffic.

Service Based Routing (SBR) has been added to the EPC by vendors to

fulfill this requirement of steering user data traffic selectively through VAS

enabler components based on user identity, mobile network information, and

service type. (Figure 4f)

Figure 4e. Options for XML based access to PCRF

MME

eNodeB SGW/PGW

PCRF

Diameter based Rx

Converter

XML based Rx AFGx (Diameter)

13

4.11 SGi traffic steering

Currently a range of Value Added Service (VAS) enablers are deployed

between P-GW SGi interface and the edge router to the Internet Service

Provider. These VAS enablers may include traffic compression, video

optimization, web caching, HTTP header enrichment, Firewall, etc. These

enablers are important for providing services in a cost efficient and stable

way. Good VAS deployment will not only improve the user experience, but

may also create additional revenue from enhancing or processing data in

accordance with business relation.

There is however a need for an efficient routing of user data traffic to avoid

unnecessary traversing of individual VAS components, which are not

needed according to the policy applicable to the specific user data traffic.

Service Based Routing (SBR) has been added to the EPC by vendors to

fulfill this requirement of steering user data traffic selectively through VAS

In Advanced EPC, SBR can be further enhanced to provide dynamic

chaining of VAS enabler components with better agility and optimization by

adopting SDN based methods. In the SDN model, VAS enabler components

will be concatenated by a programmable switch which is under the control of

a centralized SDN controller (See figure 4g). The traffic routing policy is

implemented by the interaction of SDN controller and programmable switch

based on configuration or dynamic policy control.

enabler components based on user identity, mobile network information, and

service type. (Figure 4f)

Figure 4f: Basic SBR

Figure 4g: SDN enabled SBR

SP Server

Internet

VAS 3VAS 2VAS 1

UE eNodeB RAN EPC

MME

SBRSGW/PGW

SDN Controller

Switch

SP Server

Internet

VAS 3VAS 2VAS 1

UE eNodeB RAN EPC

MME

SBRSGW/PGW

5 Conclusions

14

LTE/LTE-Advanced and the Advanced EPC are continuously developing for

meeting new or extended challenges and expectations arising from the

mobile system usage penetrating virtually any area of life and work.

The Advanced EPC delivers new key features for enhancing efficiency and

business for already deployed MBB services and applications. But the

Advanced EPC is also opening for new usages by improving system

efficiency and cost position for scenarios that are not typically broad band,

e.g. massive usage of M2M with a small amount of data, or by offering

specific features from the mobile system towards applications or service

platforms for creation of a multitude of innovative services and applications.

A main aim is always maintaining stability and robustness of the mobile

system also with the growth of volume and variety of the traffic managed by

the mobile system.

6 Annex: Abbreviation

15

CNO

CSFB

DASH

EPC

LTE

M2M

MBMS

M2M

SAPP

SBR

SDN

SIRIG

SRVCC

UPCON

VAS

XML

Core Network Overload

CS Fallback

Dynamic Adaptive Streaming over HTTP

Evolved Packet Core

Long Term Evolution

Machine-to-Machine

Multimedia Broadcast Multicast Service

Machine to Machine communication

Service Awareness & Privacy Policy

Service Based Routing

Software Defined Network

Service Identification for improved Radio utilization In GERAN

Single Radio Voice Call Continuity

User Plane CONgestion management

Value Added Server

eXtensible Markup Language

Copyright©2013 Huawei Technologies Co., Ltd. All Rights Reserved. The information contained in this document is for reference purpose only, and is subject to change or withdrawal according to specific customer requirements and conditions.


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